Refrigerating apparatus



July 7, 1936. R. R. CANDOR REFRIGERATING APPARATUS Filed Feb. 4, 1935 IN VENTOR.

R a QB p. m M o m K Patented July 7, 1936 UNITED STATES PATENT OFFICEREFRIGERATING APPARATUS poration of Delaware Application February 4,1935, Serial No. 4,834

3Claims.

This invention relates to refrigerating apparatus and more particularlyto a novel system and control'therefor for automatically varying therefrigeration output of the apparatus.

5 Heretofore, in the construction of refrigerators, particularly thosecomprising a cabinet having a food storage compartment and which areintended principally for household use, in meet-' ing the problem ofvarying the refrigeration out.- put of the machine to providesubstantially constant food preserving temperatures in the cabinet, ithas been customary to provide an automatic switch for stopping andstarting the refrigerant liquefying unit as by controlling the motorwhich drives the compressor and to thus operate the apparatusintermittently. With such a method of control. the system, while it isoperating, produces refrigeration at a substantially constant rate andthe variation in average amount of refrigerant produced over a givenperiod results in variations in the lengths of the period during whichthe machine operates or is idle. A refrigerating apparatus of thischaracter has certain disavantages, among them being high first cost andfrequent service dimculties, together with certain dimculties arisingfrom the continued stopping and starting of the refrigerant liquefyingunit, particularly with liquefying units of the compression type.

It is an object, therefore, of the present invention to provide arefrigerating apparatus which is readily adapted to extremely low costproduction and in which the difiiculties inherent in an intermittentlyoperated refrigerator are avoided.

It is a further object of the invention to provide a refrigeratingapparatus in which automatic control of the output of the apparatus isattained while the refrigerant liquefying unit is constantly running.

It is also an object of the invention to provide a refrigeratingapparatus in which the liquefying unit runs continuously throughout asubstantial range of room temperatures normally encountered and in whichsubstantially constant temperatures are maintained in the foodpreserving or other compartment to be cooled solely by controlling therate of withdrawal of vaporized refrigerant from the evaporator, and toavoid losses which may otherwise be present in such a system of control.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred form of the present invention is clearlyshown.

In the drawing:

Referring now to the drawing, the figure illustrates a diagrammatic viewof a refrigerating 5 apparatus embodying the present invention, aportion of the mechanism being shown in cross section.

In the form of the invention illustrated in the figure, there isprovided a refrigerator cabinet indicated diagrammatically at IU forminga food compartment II in which substantially constant temperatures areto be maintained throughout a wide range of room temperatures. Forexample, in an ordinary household refrigerator, it is desirable tomaintain a temperature within the compartment I2 between substantially42 and 50 F., while room temperatures may run as high as 110 and aregenerally not below 60 F. Associated with the cabinet I is arefrigerantliquefying unit comprising a compressor I mounted with amotor I 5 in a sealed housing l1, and a condenser I8, all of which maytake any of numerous suitable forms in order to maintain a constantsupply of liquefied refrigerant for use in the system. Within thecompartment l2, there is mounted a refrigerant evaporator it for forcooling the air within the compartment l2, and which may also beprovided with means for freezing water as is well known in the art.Suitable means for controlling the flow of liquid refrigerant from theliquefying unit to the evaporator are provided and may comprise a fixedrestrictor or other refrigerant control device 20. The elements so fardescribed are connected in series by suitable refrigerant conduits inthe well known manner to provide a closed refrigerant circuit. Theelements of the refrigerating system including the refrigerantliquefying unit, the liquid refrigerant control device and theevaporator are preferably so proportioned and coordinated with eachother as to provide a maximum refrigeration output not substantially inexcess of the heat load requirements of the cab- 45 inet under thehighest room temperature normally encountered.

In order to provide for a reduction in the out put of the apparatusunder conditions at which the maximum output is too great formaintaining proper temperatures within the compartment II, athermostatically controlled valve 22 is provided in the refrigerantconduit between the evaporator I 8 and the compressor ll. The valve 22comprises a housing 24 formed with a valve l win-W seat 26 adapted to beopened and closed by a valve 28. The valve 28 is moved between open andclosed positions by a bellows 30 acting through a push rod 32, adiaphragm 33 and a yoke 35. The bellows 30 is connected to athermostatic bulb 34 located in the compartment l2 and when suitablycharged with a volatile liquid, acts to open and close the valve 28 inaccordance with temperature conditions-within the compartment I2. Inorder to prevent a loss otherwise entailed in the reduction of pressureand consequent expansion of the refrigerant passing through thethermostatic valve 22, a heat interchanger 36 is provided in the conduitconnecting the valve 22 with the compressor I. This causes therefrigerant expanding from the valve 22 to withdraw heat from the liquidrefrigerant entering the restrictor 20.

In operation of the apparatus, whenever current is fed to the motor IS,the refrigerant liquefying unit comprising the motor 15, compressor I4and condenser l6 will remain in operation regardless of the loadrequirements of the evaporator l8. Refrigerant is compressed in thecompressor I 4 and delivered to the condenser l8 where it is condensedto be expanded through the restrictor 20 and vaporized in the evaporator18. The vaporized refrigerant is withdrawn from the evaporator l8through the valve 22 to be returned to the compressor H forrecompression. When the temperature within the compartment I2 is abovethe maximum desirable temperature, the thermostatic valve 22 ismaintained open by the pressure in the bellows 30, permittingrefrigeration to take place at the maximum rate of which the system iscapable. As soon as the withdrawal of heat from the air in thecompartment l2 by the evaporator I8 has reduced the temperature of theair sufficiently to bring it within the desired range, the bellows 30begins to contract and to close the valve 22. Thereafter, the withdrawalof vaporized refrigerant from the evaporator I8 is decreased until suchtime as the valve 22 again opens. It will -be noted that the refrigerantliquefying unit is maintained in continuous operation and that thetemperature of the air in compartment I2 is maintained substantiallyconstant notwithstanding the continuous operation of the refrigerantliquefying unit. By this construction, it is possible to provide arefrigerating apparatus wherein the refrigerant liquefying unit runscontinuously throughout substantially the entire range of roomtemperatures normally encountered, although if a thermostatic switch isprovided for controlling the motor-compressor I4, its cut-out point maybe selected so as to provide intermittent operation of the liquefyingunit below any desired room temperature less than maximum. Theefficiency of the apparatus while operating at reduced load ismaintained by the operation of the heat interchanger 36 which causes therefrigerant expanding from the valve 22 to absorb heat from the warmliquid refrigerant entering the restrictor 20.

Thus, the present invention provides a refrigerating apparatus havingmeans for maintaining the temperature of the compartment to be cooledwithin a predetermined range, while the refrigerating apparatus for thecompartment is maintained in continuous operation.

While the form of embodiment of the present invention as hereindisclosed constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. A unitary household refrigerating apparatus comprising a cabinet tobe cooled, at refrigerant liquefying unit, an evaporator in heat exchange relation to the air in said cabinet, a fixed orifice restrictorbetween said liquefying unit and evaporator, thermostatic means forcontrolling the entire flow of refrigerant from the evaporator to theliquefying unit to vary the amount of refrigeration produced by saidapparatus while maintaining said liquefying unit in operation whereby tomaintain substantially constant temperatures in said cabinet, and a heatinterchanger for exchanging heat between the cold gas leaving saidthermostatic means and the liquid refrigerant leaving the liquefyingunit.

2. A unitary household refrigerating apparatus comprising a cabinet tobe cooled, a refrigerant liquefying unit, an evaporator in heat exchangerelation to the air in said cabinet, a fixed orifice restrictor betweensaid liquefying unit and evaporator, thermostatic means including avalve for controlling the entire flow of refrigerant from the evaporatorto the liquefying unit to vary the amount of refrigeration produced bysaid apparatus while maintaining said liquefying unit in operationwhereby to maintain substantially constant temperatures in said cabinet,and a heat interchanger for exchanging heat betweeen the cold gasleaving said thermostatic valve means and the liquid refrigerant leavingthe liquefying unit.

3. Refrigerating apparatus comprising, means forming a space to berefrigerated, an evaporator in heat exchange relation to the air to becooled for said space, a refrigerant liquefying unit, a fixed orificerestrictor between said liquefying unit and evaporator, an evaporatedrefrigerant line between said evaporator and liquefying unit, heatexchange means between liquid refrigerant flowing between saidliquefying unit and restrictor with refrigerant flowing from saidevaporator to said liquefying unit, and a thermostatically controlledthrottling valve in said evaporated refrigerant line between saidevaporator and said heat exchanger.

' ROBERT R. CANDOR.

